An apparatus for frothing milk is known, for example, from EP 1 501 398. In the apparatus described there the open end of a so-called conveyor pipe is submerged in a vessel containing milk. A steam generator is connected to the conveyor pipe by a first pipe, and a compressed air source is connected to the conveyor pipe by a second pipe. Both pipes are brought together and then lead to the conveyor pipe, so that a steam/air mixture is conducted through the conveyor pipe into the milk contained in the vessel.
A frothing apparatus for the frothing of milk is also known from DE 44 45 436. In this frothing apparatus steam is conducted from a steam generator through a steam supply conduit, milk is conducted through a milk supply conduit and air is conducted through an air supply conduit into a mixing chamber where they are mixed, and are subsequently pressed into a frothing chamber where the milk is frothed.
Other frothing apparatus are known, for example, from DE 10 2009 025 986, EP 2 025 270, EP 1 747 743 or WO 2004/089173.
The frothing apparatuses known in the prior art have the drawback that the injection of cold air into the steam conduit and the mixing chamber leads to a higher condensation of the steam and, thus, to a deterioration of the frothing process.